1. Field of the Invention
The present invention relates to a hard disk drive (HDD), and more particularly, to an HDD and method for suppressing turbulence during the rotation of a HDD disk.
2. Description of the Related Art
Hard disk drives (HDDs), which are auxiliary memory devices for computers, reproduce information stored in a magnetic disk or record new information on the magnetic disk by way of a magnetic head. There have been demands for HDDs to have higher capacity and operate at higher speeds with lower vibrations. To meet these demands, extensive research and development efforts have been made.
FIG. 1 is an exploded perspective view of a conventional HDD disclosed in Korean Patent Publication No. 2003-68261.
Referring to FIG. 1, a HDD 10 includes a pair of disks 20 and 22, which are data recording media having a spacer 25 therebetween, a spindle motor 30 that is installed on a base member 11 and rotates the disks 20 and 22, an actuator 40 that includes a magnetic head (not shown) for recording or reproducing data on the disks 20 and 22 and for moving the magnetic head, and a cover member 15 that is attached to the base member 11 to protect the disks 20 and 22, the spindle motor 30, and the actuator 40 on the base member 11.
The disks 20 and 22 are fixed on a rotor of the spindle motor 30 so as to rotate relative to the base member 11. Servo signals indicating positions of data recorded or to be recorded are previously recorded on tens of thousands of tracks on surfaces of the respective disks 20 and 22 along the circumferences of the disks 20 and 22.
The actuator 40, which is driven by a voice coil motor 48, rotates around a pivot bearing 47 that is installed on the base member 11. The actuator 40 includes a swing arm 42 that is pivotably coupled to the pivot bearing 47, and a suspension 43 that elastically biases a slider 45, on which the magnetic head is mounted, toward the surfaces of the respective disks 20 and 22.
If the HDD 10 is turned on and the disks 20 and 22 begin to rotate, a lifting force is generated due to an air pressure difference. Accordingly, the slider 45 is maintained over the surfaces of the respective disks 20 and 22 at a height where the lifting force generated from the rotation of the disks 20 and 22 is equal to an elastic force of the suspension 43. Consequently, the magnetic head mounted on the slider 45 records or reproduces data on the disks 20 and 22 while maintaining a predetermined distance from the respective disks 20 and 22.
As such, the conventional HDD 10 suffers from vibrations due to structural defects of the spindle motor 30, assembly errors of the disks 20 and 22, and turbulent air flow in the HDD 10, for example. Such vibrations cause position error signals (PESs) and negatively affect recording and reproducing operations of the HDD 10.
A recent attempt to use a hydrodynamic bearing in the spindle motor 30 of the HDD has considerably reduced vibrations in comparison to spindle motors using ball bearings. Accordingly, turbulent air flow from the high speed rotation of the disks 20 and 22 has become the primary cause of vibrations of the HDD 10. Several approaches have been made to suppress the turbulent air flow, for example, by forming grooves 12 and 16 on surfaces of the base member 11 and the cover member 15, which face the disks 20 and 22, respectively. Another method includes forming a blade (not shown). However, if the grooves 12 and 16 or the blade is applied to the HDD 10 as shown in FIG. 1, the grooves 12 and 16 or the blade would still only fail to control the air flow between the inner surfaces of the disks 20 and 22, which do not respectively face the base member 11 and the cover member 15. In addition, neither grooves 12 and 16, nor the blade, suppress vibrations of the actuator 40.